Android - HTTP POST

AndroidManifest.xml

<?xml ... >
<manifest ... >
  
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <application ... />
</manifest>

CallAPI.java

public class CallAPI extends AsyncTask<String, String, String> {

    public CallAPI() {
        //set context variables if required
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected String doInBackground(String... params) {
        String urlString = params[0]; // URL to call
        String data = "data=" + params[1]; //data to post
        OutputStream out = null;

        try {
            URL url = new URL(urlString);
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setDoOutput(true);
            //urlConnection.setRequestMethod("POST");
            out = new BufferedOutputStream(urlConnection.getOutputStream());

            // Send POST data request
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8));
            writer.write(data);
            writer.flush();
            writer.close();
            out.close();

            // Get the server response
            BufferedReader reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
            StringBuilder sb = new StringBuilder();
            String line = null;

            // Read server response
            while ((line = reader.readLine()) != null) {
                //Append server response in string
                sb.append(line + "\n");
            }

            String text = sb.toString();
            Log.d("SERVER RESPONSE", text);

            //urlConnection.connect();
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }

        return urlString;
    }
}

index.php

<?php

if ($_POST["data"]) {
    $data = $_POST["data"].PHP_EOL;

    $fp = fopen("db", "a");
    fwrite($fp, $data);

    print "Data : $data";
} else print
    <<<TAG
            <form action="index.php" method="post">
                TEST : <input type="text" name="data" />
                <input type="submit" value="submit" />
            </form>
        TAG;

MainActivity.java

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home_layout);
      
        callAPI.execute("http://192.168.1.1/", "Data from android");
     
    }